A funeral has been held in Chicago for a young African-American woman who was found dead in her jail cell as hundreds of protesters gathered in the US state of New Jersey to campaign against police brutality and racial injustice.

Sandra Bland, 28, died three days after she was arrested for a minor traffic violation in Texas.

Family and friends of the Illinois woman remembered her on Saturday as a "courageous voice" for social justice and promised to keep fighting for clarity on the circumstances surrounding her death.

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Hundreds of people celebrated her life at the funeral, but some also said they were still struggling to understand how a traffic stop for failing to use a turn signal escalated into a physical confrontation and landed her in the cell where authorities say she killed herself three days later.

The Harris County, Texas, medical examiner's office determined through an autopsy that Bland hanged herself with a plastic bag.

Bland's family has questioned the finding, saying she was excited about starting a new job and wouldn't have taken her own life.

Reverend Theresa Dear told reporters outside the DuPage African Methodist Episcopal Church that friends and family continued to have those doubts, even as authorities released documents in support of their conclusion that it was suicide.

"When you are about to start a new job, when you know your family is about to bring the money for your release, when you are an activist and a fighter, you don't take your own life," she said.

The traffic stop, which was captured on police dash cam video and on a bystander's mobile phone, and Bland's death in custody have resonated on social media, with many grouping it with other prominent US cases involving confrontations between the police and blacks over the past year.

A protester demonstrates outside the funeral for Sandra Bland in Chicago as hundreds of others gathered in Newark [Reuters]

Bland had spoken out about that issue and others in a series of videos she posted online this year with the hashtag "SandySpeaks."

Mourners at Saturday's funeral wore T-shirts with the tag. One person had it scrawled across a car window. Some took to Twitter with the hashtag " SandySTILLSpeaks."

Momentum 'growing'

Al Jazeera's Andy Gallacher, reporting from Newark, said the protest over racial intolerance was planned in January but events of the past few months "have brought things into sharp focus".

In April a video showing Walter Scott being shot as he was running away from a white police officer in Charleston, South Carolina, made global headlines.

Also at a Charleston church last month, nine black people were killed when a white man opened fire during a Bible study session.

"Momentum for these kinds of events is growing across the United States and organisers here say as long as this list of names keeps on growing they will keep on pushing for real and lasting change," our correspondent said.

"The slogan 'black lives matter' has now become a rallying cry for people across the US and their calls for reform seem to be gathering pace."

Michele Kamal, whose 23-year-old son Abdul was killed by police two years ago, urged others to take to the streets.

"I've always been one on the sidelines looking saying wow, that's sad, but it knocked on my door so now I'm here and what we want people [to do is] not to wait until it happens to you," she told Al Jazeera.

"Get involved in a reputable organisation, you know, to let people know that this is a serious thing!"

Source: Al Jazeera And AP